A favorite technique of guerrilla gardeners that I recently had the pleasure of experiencing myself: throwing seed bombs. These are little hand-formed balls of soil and seeds that people can create en masse, then carry with them wherever they go. Most often they contain local wildflower seeds, but anything goes when you’re a guerrilla. In theory you can toss them wherever you see empty land that could benefit from a bit of green—under an overpass, alongside the road, in a vacant lot. Once you lob them grenade-style over a fence (or bury them with more care where possible), they’ve got everything they need to germinate and take over from there as only wildflowers can.
As for me, I’ve yet to interfere with public landscaping. I guess I’m a pacifist, even by gardening standards. But I did get a seed bomb labeled “High Desert Wildflower Mix” at the Albuquerque seed swap a couple months ago, and thoroughly enjoyed tossing it into the yard. The food garden will receive most of my attentions in the months ahead, but won’t it be lovely if wisteria, yucca, prickly pear, and wildflowers come up all around too?